rsync uses the GNU long options package.
Many of the command line options have two variants, one short and one long.
These are shown below, separated by commas.
Some options only have a long variant.
The '=' for options that take a parameter is optional; whitespace can be used instead.

-h, --help
Print a short help page describing the options available in rsync
--version
print the rsync version number and exit
-v, --verbose
This option increases the amount of information you are given during the transfer.
By default, rsync works silently.
A single -v will give you information about what files are being transferred
and a brief summary at the end.
Two -v flags will give you information on what files are being skipped and
slightly more information at the end.
More than two -v flags should only be used if you are debugging rsync.
-q, --quiet
This option decreases the amount of information you are given during the transfer,
notably suppressing information messages from the remote server.
This flag is useful when invoking rsync from cron.
-I, --ignore-times
Normally rsync will skip any files that are already the same length and
have the same time-stamp. This option turns off this behavior.
--size-only
Normally rsync will skip any files that are already the same length and
have the same time-stamp.
With the --size-only option files will be skipped if they have the same size,
regardless of timestamp. This is useful when starting to use rsync after
using another mirroring system which may not preserve timestamps exactly.
--modify-window
When comparing two timestamps rsync treats the timestamps as being equal if
they are within the value of modify_window.
This is normally zero, but you may find it useful to set this to a larger value
in some situations. In particular, when transferring to/from FAT filesystems
which cannot represent times with a 1 second resolution this option is useful.
-c, --checksum
This forces the sender to checksum all files using a 128-bit MD4 checksum
before transfer. The checksum is then explicitly checked on the receiver and
any files of the same name which already exist and have the same checksum and
size on the receiver are skipped. This option can be quite slow.
-a, --archive
This is equivalent to -rlptgoD. It is a quick way of saying you want recursion and
want to preserve almost everything.
Note however that -a does not preserve hardlinks, because finding multiply-linked
files is expensive. You must separately specify -H.
-r, --recursive
This tells rsync to copy directories recursively.
If you don't specify this then rsync won't copy directories at all.
-R, --relative
Use relative paths. This means that the full path names specified on the
command line are sent to the server rather than just the last parts of the
filenames. This is particularly useful when you want to send several different
directories at the same time.
For example, if you used the command
rsync foo/bar/foo.c remote:/tmp/
then this would create a file called foo.c in /tmp/ on the remote machine.
If instead you used
rsync -R foo/bar/foo.c remote:/tmp/
then a file called /tmp/foo/bar/foo.c would be created on the remote machine.
The full path name is preserved.
-b, --backup
With this option preexisting destination files are renamed with a ~ extension as
each file is transferred.
You can control the backup suffix using the --suffix option.
--backup-dir=DIR
In combination with the --backup option, this tells rsync to store all
backups in the specified directory. This is very useful for incremental backups.
--suffix=SUFFIX
This option allows you to override the default backup suffix
used with the -b option. The default is a ~.
-u, --update
This forces rsync to skip any files for which the destination file already
exists and has a date later than the source file.
-l, --links
When symlinks are encountered, recreate the symlink on the destination.
-L, --copy-links
When symlinks are encountered, the file that they point to is copied,
rather than the symlink.
--copy-unsafe-links
This tells rsync to copy the referent of symbolic links that point outside
the source tree. Absolute symlinks are also treated like ordinary files,
and so are any symlinks in the source path itself when --relative is used.
--safe-links
This tells rsync to ignore any symbolic links which point outside the
destination tree. All absolute symlinks are also ignored.
Using this option in conjunction with --relative may give unexpected results.
-H, --hard-links
This tells rsync to recreate hard links on the remote system to be the same
as the local system. Without this option hard links are treated like regular files.
Note that rsync can only detect hard links if both parts of the link are
in the list of files being sent.
This option can be quite slow, so only use it if you need it.
-W, --whole-file
With this option the incremental rsync algorithm is not used and the whole
file is sent as-is instead. The transfer may be faster if this option is
used when the bandwidth between the source and target machines is higher
than the bandwidth to disk (especially when the "disk" is actually a networked file system).
This is the default when both the source and target are on the local machine.
-p, --perms
This option causes rsync to update the remote permissions to be the same as
the local permissions.
-o, --owner
This option causes rsync to set the owner of the destination file to be the
same as the source file. On most systems, only the super-user can set file ownership.
-g, --group
This option causes rsync to set the group of the destination file to be the
same as the source file. If the receiving program is not running as the super-user,
only groups that the receiver is a member of will be preserved
(by group name, not group id number).
-D, --devices
This option causes rsync to transfer character and block device information to
the remote system to recreate these devices.
This option is only available to the super-user.
-t, --times
This tells rsync to transfer modification times along with the files and update
them on the remote system. Note that if this option is not used,
the optimization that excludes files that have not been modified cannot be effective;
in other words, a missing -t or -a will cause the next transfer to behave as if
it used -I, and all files will have their checksums compared and show up in log
messages even if they haven't changed.
-n, --dry-run
This tells rsync to not do any file transfers, instead it will just report the
actions it would have taken.
-S, --sparse
Try to handle sparse files efficiently so they take up less space on the
destination.
NOTE: Don't use this option when the destination is a Solaris "tmpfs" filesystem.
It doesn't seem to handle seeks over null regions correctly and ends up corrupting
the files.
-x, --one-file-system
This tells rsync not to cross filesystem boundaries when recursing.
This is useful for transferring the contents of only one filesystem.
--existing
This tells rsync not to create any new files - only update files that already
exist on the destination.
--max-delete=NUM
This tells rsync not to delete more than NUM files or directories.
This is useful when mirroring very large trees to prevent disasters.
--delete
This tells rsync to delete any files on the receiving side that aren't on
the sending side. Files that are excluded from transfer are excluded from
being deleted unless you use --delete-excluded.
This option has no effect if directory recursion is not selected.
This option can be dangerous if used incorrectly! It is a very good idea to
run first using the dry run option (-n) to see what files would be deleted
to make sure important files aren't listed.
If the sending side detects any IO errors then the deletion of any files at
the destination will be automatically disabled.
This is to prevent temporary filesystem failures (such as NFS errors) on the
sending side causing a massive deletion of files on the destination.
You can override this with the --ignore-errors option.
--delete-excluded
In addition to deleting the files on the receiving side that are not on
the sending side, this tells rsync to also delete any files on the receiving side
that are excluded (see --exclude).
--delete-after
By default rsync does file deletions before transferring files to try to
ensure that there is sufficient space on the receiving filesystem.
If you want to delete after transferring then use the --delete-after switch.
--ignore-errors
Tells --delete to go ahead and delete files even when there are IO errors.
--force
This options tells rsync to delete directories even if they are not empty.
This applies to both the --delete option and to cases where rsync tries to
copy a normal file but the destination contains a directory of the same name.
Since this option was added, deletions were reordered to be done depth-first
so it is hardly ever needed anymore except in very obscure cases.
-B , --block-size=BLOCKSIZE
This controls the block size used in the rsync algorithm.
See the technical report for details.
-e, --rsh=COMMAND
This option allows you to choose an alternative remote shell program to
use for communication between the local and remote copies of rsync.
By default, rsync will use rsh, but you may like to instead use ssh because
of its high security.
You can also choose the remote shell program using the RSYNC_RSH
environment variable.
See also the --blocking-io option which is affected by this option.
--rsync-path=PATH
Use this to specify the path to the copy of rsync on the remote machine.
Useful when it's not in your path. Note that this is the full path to the binary,
not just the directory that the binary is in.
--exclude=PATTERN
This option allows you to selectively exclude certain files from the list of
files to be transferred.
This is most useful in combination with a recursive transfer.
You may use as many --exclude options on the command line as you like to
build up the list of files to exclude.
See the section on exclude patterns for information on the syntax of this option.
--exclude-from=FILE
This option is similar to the --exclude option, but instead it adds all exclude
patterns listed in the file FILE to the exclude list.
Blank lines in FILE and lines starting with ';' or '#' are ignored.
--include=PATTERN
This option tells rsync to not exclude the specified pattern of filenames.
This is useful as it allows you to build up quite complex exclude/include rules.
See the section of exclude patterns for information on the syntax of this option.
--include-from=FILE
This specifies a list of include patterns from a file.
-C, --cvs-exclude
This is a useful shorthand for excluding a broad range of files that you often
don't want to transfer between systems.
It uses the same algorithm that CVS uses to determine if a file should be ignored.
The exclude list is initialized to:
RCS SCCS CVS CVS.adm RCSLOG cvslog.* tags TAGS .make.state .nse_depinfo *~ #* .#* ,* *.old *.bak *.BAK *.orig *.rej .del-* *.a *.o *.obj *.so *.Z *.elc *.ln core
then files listed in a $HOME/.cvsignore are added to the list and any files
listed in the CVSIGNORE environment variable (space delimited).
Finally, any file is ignored if it is in the same directory as a .cvsignore file
and matches one of the patterns listed therein.
See the cvs(1) manual for more information.
--csum-length=LENGTH
By default the primary checksum used in rsync is a very strong 16 byte MD4 checksum.
In most cases you will find that a truncated version of this checksum is quite
efficient, and this will decrease the size of the checksum data sent over the link,
making things faster.
You can choose the number of bytes in the truncated checksum
using the --csum-length option. Any value less than or equal to 16 is valid.
Note that if you use this option then you run the risk of ending up with an
incorrect target file. The risk with a value of 16 is microscopic and can be
safely ignored (the universe will probably end before it fails)
but with smaller values the risk is higher.
Current versions of rsync actually use an adaptive algorithm for the checksum
length by default, using a 16 byte file checksum to determine if a 2nd pass is
required with a longer block checksum.
Only use this option if you have read the source code and know what you are doing.
-T, --temp-dir=DIR
This option instructs rsync to use DIR as a scratch directory when creating
temporary copies of the files transferred on the receiving side.
The default behavior is to create the temporary files in the receiving directory.
--compare-dest=DIR
This option instructs rsync to use DIR on the destination machine as an
additional directory to compare destination files against when doing transfers.
This is useful for doing transfers to a new destination while leaving existing
files intact, and then doing a flash-cutover when all files have been successfully
transferred (for example by moving directories around and removing the old
directory, although this requires also doing the transfer with -I to avoid
skipping files that haven't changed).
This option increases the usefulness of --partial because partially transferred
files will remain in the new temporary destination until they have a chance to be
completed. If DIR is a relative path, it is relative to the destination directory.
-z, --compress
With this option, rsync compresses any data from the files that it sends to the
destination machine. This option is useful on slow links. The compression method
used is the same method that gzip uses.
Note this this option typically achieves better compression ratios that can be
achieved by using a compressing remote shell, or a compressing transport,
as it takes advantage of the implicit information sent for matching data blocks.
--numeric-ids
With this option rsync will transfer numeric group and user ids rather than
using user and group names and mapping them at both ends.
By default rsync will use the user name and group name to determine what
ownership to give files. The special uid 0 and the special group 0 are never
mapped via user/group names even if the --numeric-ids option is not specified.
If the source system is a daemon using chroot, or if a user or group name
does not exist on the destination system, then the numeric id from the
source system is used instead.
--timeout=TIMEOUT
This option allows you to set a maximum IO timeout in seconds.
If no data is transferred for the specified time then rsync will exit.
The default is 0, which means no timeout.
--daemon
This tells rsync that it is to run as a daemon.
The daemon may be accessed using the host::module or rsync://host/module/ syntax.
If standard input is a socket then rsync will assume that it is being
run via inetd, otherwise it will detach from the current terminal and
become a background daemon. The daemon will read the config file (/etc/rsyncd.conf)
on each connect made by a client and respond to requests accordingly.
See the rsyncd.conf(5) man page for more details.
--no-detach
When running as a daemon, this option instructs rsync to not detach itself and
become a background process.
This option is required when running as a service on Cygwin, and may also be useful
when rsync is supervised by a program such as daemontools or AIX's System Resource
Controller. --no-detach is also recommended when rsync is run under a debugger.
This option has no effect if rsync is run from inetd or sshd.
--address
By default rsync will bind to the wildcard address when run as a daemon with
the --daemon option or when connecting to a rsync server.
The --address option allows you to specify a specific IP address (or hostname) to
bind to. This makes virtual hosting possible in conjunction with the --config option.
--config=FILE
This specifies an alternate config file than the default /etc/rsyncd.conf.
This is only relevant when --daemon is specified.
--port=PORT
This specifies an alternate TCP port number to use rather than the default port 873.
--blocking-io
This tells rsync to use blocking IO when launching a remote shell transport.
If -e or --rsh are not specified or are set to the default "rsh",
this defaults to blocking IO, otherwise it defaults to non-blocking IO.
You may find the --blocking-io option is needed for some remote shells that can't
handle non-blocking IO. Ssh prefers blocking IO.
--log-format=FORMAT
This allows you to specify exactly what the rsync client logs to stdout on
a per-file basis. The log format is specified using the same format conventions
as the log format option in rsyncd.conf.
--stats
This tells rsync to print a verbose set of statistics on the file transfer,
allowing you to tell how effective the rsync algorithm is for your data.
--partial
By default, rsync will delete any partially transferred file if the transfer
is interrupted. In some circumstances it is more desirable to keep partially
transferred files. Using the --partial option tells rsync to keep the partial
file which should make a subsequent transfer of the rest of the file much faster.
--progress
This option tells rsync to print information showing the progress of the transfer.
This gives a bored user something to watch.
This option is normally combined with -v. Using this option without the -v option
will produce weird results on your display.
-P
The -P option is equivalent to --partial --progress.
I found myself typing that combination quite often so I created an option to make
it easier.
--password-file
This option allows you to provide a password in a file for accessing a
remote rsync server. Note that this option is only useful when accessing a
rsync server using the built in transport, not when using a remote shell as
the transport. The file must not be world readable.
It should contain just the password as a single line.
--bwlimit=KBPS
This option allows you to specify a maximum transfer rate in kilobytes per second.
This option is most effective when using rsync with large files
(several megabytes and up). Due to the nature of rsync transfers,
blocks of data are sent, then if rsync determines the transfer was too fast,
it will wait before sending the next data block.
The result is an average transfer rate equalling the specified limit.
A value of zero specifies no limit.
--read-batch
Apply a previously generated change batch.
--write-batch
Generate a set of files that can be transferred as a batch update.
EXIT VALUES
RERR_SYNTAX 1
Syntax or usage error
RERR_PROTOCOL 2
Protocol incompatibility
RERR_FILESELECT 3
Errors selecting input/output files, dirs
RERR_UNSUPPORTED 4
Requested action not supported: an attempt was made to manipulate
64-bit files on a platform that cannot support them; or an option was
speciifed that is supported by the client and not by the server.
RERR_SOCKETIO 10
Error in socket IO
RERR_FILEIO 11
Error in file IO
RERR_STREAMIO 12
Error in rsync protocol data stream
RERR_MESSAGEIO 13
Errors with program diagnostics
RERR_IPC 14
Error in IPC code
RERR_SIGNAL 20
Received SIGUSR1 or SIGINT
RERR_WAITCHILD 21
Some error returned by waitpid()
RERR_MALLOC 22
Error allocating core memory buffers
RERR_TIMEOUT 30
Timeout in data send/receive

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